1. Field of the Invention
The present invention relates to a device for compressive molding a stream of filler for a tobacco rod to a predetermined cross-sectional shape before the tobacco rod is continuously formed in a cigarette manufacturing machine.
2. Description of the Related Art
The cigarette manufacturing machine comprises a compression molding device for compressing a stream of filler including cut tobacco, and molding it to a predetermined cross-sectional shape, i.e., a cross-sectional circle. Such a stream compression molding stabilizes the forming of tobacco rod, i.e., filler wrapping with paper.
The compression molding device comprises a molding bed for guiding a filler stream with paper, and a compression mold arranged at the upper side of the bed, the so-called tongue, the tongue defining a compression molding passage for the stream between the bed and the tongue.
Since the tongue is fixed, the stream receives large resistance from the tongue when the filler stream passes through the compression molding passage. When flowing resistance of the stream of filler is large, the cut tobacco is liable to be overheated, and the crush of the cut tobacco is increased. Overheating of the cut tobacco results in a loss of the tase of any cigarettes obtained from the tobacco rod. The crush of the cut tobacco not only causes unstable tobacco rod forming itself, that is, filler wrapping with paper, but also generates soft spots having a low filler density in connection with filler in the tobacco rod. The presence of soft spots is liable to cause the dropout of filler or cut tobacco form the cut end of cigarette rod or cigarette obtained by cutting the tobacco rod.